Answer:
30. 2x²-x-1=0
or, 2x²-2x+x-1=0
or, 2x(x-1)+1(x-1)=0
or, (x-1)(2x+1)=0
so, x-1 = 0 or, x = 1
and 2x+1 = 0 or, 2x = -1 or, x = -1/2
so, x = 1 and 1/2
31. 3x²-14x=5
or, 3x²-14x-5=0
or, 3x²-15x+x-5=0
or, 3x(x-5)+1(x-5)=0
or, (x-5)(3x+1)=0
so, x-5=0 or, x=5
and 3x+1=0 or, 3x=-1 or, x=-1/3
so, x = 5 and -1/3
Answered by GAUTHMATH